JPS6084920A - Power factor detecting relay system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an external accident detection method in a solar power generation device or the like.

[Background of the invention]

If a self-cooling type solar generator is installed and an accident occurs on the distribution system while it is operating in connection with the distribution system, the accident charge will flow from the solar power generation device to the grid. Due to the characteristics of solar cells, there is not much difference between the fault current value and the steady load current value, so the fault detection method becomes a problem.

FIG. 1 shows the voltage-current characteristics of a solar cell.

The current value in the case of a short circuit accident, that is, when the voltage is zero, is only about 1.1 to 1.2 times the rated current. Due to such electric characteristics, conventionally considered detection methods have the following problems.

(1) With the overcurrent detection method, it is difficult to set the detection level because there is not much difference in current value between an accident and a steady state.

(2) With the undervoltage detection method, sufficient detection cannot be obtained in the event of a distant accident, and there is a possibility of false detection when starting the motor, etc.

(3) The tidal current direction detection method that detects the reversal of the tide direction cannot be applied to a method in which all power is supplied from the solar starter device to the distribution system, that is, a method that allows reverse tidal flow.

[Purpose of the invention]

Is this the purpose of the present invention? The purpose of the present invention is to provide a detection method that can also be applied to battery characteristics.

[Embodiments of the invention]

The present invention will be explained in detail below.

Figure 2 shows the solar power generation device 1 of the present invention.
This is a detection circuit. In Figure 2, solar power generation device 1
The circuit voltage and circuit 'it#Lk are connected to the connection point with the distribution system.
Input power factor detection V-(P(JWEI%FA, CTO
RRELAY (hereinafter referred to as PFHY) is installed to detect accidents. Here, the conditions that P F RY must meet are: (1) There should be no malfunction when starting the motor, etc.
J(2) Ensure reliable operation in the event of a near-end or far-end accident. In the figure, 2 is a solar cell, 3 is an inverter, and 4 is a conversion transformer.

In order to satisfy all of these two conditions, the operating characteristics of PL''Y need to be as shown in FIG.

In FIG. 3, the horizontal axis shows effective force P, and the vertical axis shows reactive force Q, and the operating point during steady state is where the power factor is close to 1. However, when an accident occurs, the operating point during normal operation moves to the line angle of the power distribution line. Therefore, the operating range of the PFRY should be the shaded area that includes the line angle of the power distribution line, but in order to prevent malfunctions such as when starting the motor, it is necessary to delete the entire operating range as shown in the figure. .

In addition, since PB'l (, Y has no directionality, V?1 malfunctions in the event of an accident on the solar power generation equipment side (internal accident), and the time is set so that it works faster than NFHt-PF)LY in Figure 2. It is necessary to prevent malfunctions by coordinating.

〔Effect of the invention〕

According to the present invention, external faults can be detected even in systems other than solar power generation devices in which there is not much difference between the load current value during steady state and the short-circuit current value at the time of fault.

[Brief explanation of the drawing]

Fig. 1 is a voltage-current characteristic diagram of a solar cell, Fig. 2 is a detection circuit diagram to which the PFHY of the present invention is applied, and Fig. 3 is a PFR
FIG. CT...Current transformer, PT...Voltage transformer, P F
RY...Power factor detection V-1NFB...No fuse nooker, P...active power, Q...invalid torque. First country yoke (Pυ), / □P

Claims (1)

[Claims] 1. In a circuit where there is not much difference between the steady load current value and the short-circuit current value at the time of an accident, it is possible to detect an accident by detecting the power factor of this circuit. Features a single-type power factor detection relay.